<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
       "http://www.w3.org/TR/html4/strict.dtd">
<html>
<script type="text/javascript" src="http://dsbe-demo.saffre-rumma.net/media/tinymce/tiny_mce.js"></script>
<script type="text/javascript">
tinyMCE.init({
    mode : "textareas",
    theme : "advanced"
});

function ajaxLoad() {
    var ed = tinyMCE.get('content');

    // Do you ajax call here, window.setTimeout fakes ajax call
    ed.setProgressState(1); // Show progress
    window.setTimeout(function() {
        ed.setProgressState(0); // Hide progress
        ed.setContent('HTML content that got passed from server.');
    }, 3000);
}

function ajaxSave() {
    var ed = tinyMCE.get('content');

    // Do you ajax call here, window.setTimeout fakes ajax call
    ed.setProgressState(1); // Show progress
    window.setTimeout(function() {
        ed.setProgressState(0); // Hide progress
        alert(ed.getContent());
    }, 3000);
}
</script>

<form method="post" action="somepage">
    <textarea name="content" style="width:100%">
    </textarea>
    <input type="button" onclick="ajaxLoad()" value="Load"/>
    <input type="button" onclick="ajaxSave()" value="Save"/>
</form>
</html>